| Case | Tank Type | Main Inputs | Capacity | Excavation | Backfill | Uplift Safety Factor |
|---|---|---|---|---|---|---|
| Example A | Horizontal Cylindrical | Length 6.0 m, Diameter 2.5 m, Cover 1.2 m | 29.45 m³ | 130.42 m³ | 84.21 m³ | 3.57 |
| Example B | Rectangular | Length 5.0 m, Width 2.5 m, Height 2.0 m | 25.00 m³ | 101.52 m³ | 60.74 m³ | 3.32 |
The calculator uses practical construction approximations for sizing, excavation, and uplift review.
Horizontal cylindrical uplift uses a circular segment for partial submergence. Excavation is modeled as a rectangular prism. Soil cover is based on the tank top projection area.
- Choose the tank shape first.
- Enter internal tank dimensions in meters.
- Add wall thickness, cover depth, and clearances.
- Enter bedding and base slab thicknesses.
- Set groundwater height for uplift evaluation.
- Enter fill percentage and stored liquid density.
- Review soil, concrete, and tank unit weights.
- Click calculate to show results above the form.
- Use CSV or PDF buttons to export the summary.
1) What does this calculator estimate?
It estimates tank capacity, outside dimensions, excavation size, bedding quantity, concrete base volume, backfill quantity, uplift force, and uplift safety factor for buried construction tanks.
2) Can I compare cylindrical and rectangular tanks?
Yes. Select either horizontal cylindrical or rectangular geometry. The form updates relevant dimension fields, then the calculation adjusts volume and buoyancy methods accordingly.
3) Why is groundwater height important?
Groundwater creates buoyant uplift. Higher water levels increase displaced volume and upward force. This check helps you assess whether soil cover, contents, and base slab weight provide enough resistance.
4) Does the calculator include the tank self weight?
Yes. It estimates shell volume from outside and inside geometry, then multiplies that shell volume by the user-entered tank material unit weight.
5) Is excavation modeled with sloped sides?
No. This version assumes a rectangular excavation prism. That keeps quantity planning simple, but you should adjust manually if your trench support or side slopes change the actual excavation shape.
6) What fill percentage should I use?
Use the normal operating liquid level, not only the tank maximum. Partial contents change resisting weight, so a realistic operating percentage gives a better uplift review.
7) Is this suitable for final structural design?
It is best for planning, checking, and early design review. Final design should still follow project drawings, geotechnical data, codes, manufacturer details, and engineer approval.
8) What should I do if the uplift safety factor is low?
Consider a thicker base, hold-down anchors, greater cover, heavier tank construction, lower groundwater assumptions only when justified, or updated operating conditions verified by design professionals.